Psychology 2221B Chapter Notes - Chapter 4: Resting Potential, Axon Hillock, Axon Terminal

• School: Western University
• Department: Psychology
• Course: Psychology 2221B
• Professor: Shelley Cross- Mellor

Document Summary

Membrane potential is the difference in electrical charge between the inside and the outside of a cell. To record a neuron"s membrane potential, it is necessary to position the tip of one electrode inside the neuron and the tip of another electrode outside the neuron in the extracellular fluid. The intracellular electrodes are called microelectrodes: their tips are less than one thousandth of a millimeter in diameter much too small to be seen by the naked eye. When both electrode tips are in the extracellular fluid, the voltage difference between them is zero. With the -70 mv charge built up across its membrane, a neuron is said to be polarized. The salts in neural tissue separate into positively and negatively charged particles called ions. Four kinds of ions contribute significantly to the resting potential: sodium ions (na+), potassium ions (k+), chloride ions (cl-), and various negatively charged protein ions.